1. Field of the Invention
The invention is located in the field of conveying flat, bendable objects, in particular printed products, and it concerns a device according to the generic term of the independent claim. The device serves for the separation of individual flat, bendable printed products from the underside of a stack of such objects and for the onward transportation of these objects, in particular for the separation of individual printed products from the underside of a stack of printed products and for onward transportation of the printed products.
2. Description of Related Art
From publication EP-1226083, a device is known which serves the purpose named above. For separation of individual printed products from the underside of the stack of printed products, the device includes a carrier wheel, arranged below the stack, rotating on a substantially horizontal axis, on the periphery of which pairs, each consisting of a suction device and a gripper allocated to the suction device, are arranged. The device further includes a supporting means, which on the one hand supports the stack from below, and on the other hand includes at least one extraction opening, through which the lowermost printed product may be gripped and for separation may be bent away from the stack towards the gripper allocated to the suction device.
The carrier wheel is arranged and driven such that the suction device and gripper are moved in parallel to a pair of edges of the stacked printed products and approximately centrally between these edges below the stack. The suction devices are rotated in a controlled manner during the rotation of the carrier wheel and connected to a suction pipe and de-coupled from it. The grippers are closed and re-opened in a controlled manner during the rotation. When a suction device is moved underneath the stack, it grips the lowermost printed product in the region of the edge orientated transversally to its direction of movement it meets first and when moving further it bends this edge region downwards through the extraction opening in the supporting means into the open gripper mouth of the allocated gripper, which then grips the printed product and removes it completely from the stack during its further movement.
In an embodiment described in publication EP-1226083, the supporting means on which the stack rests is a roll bed conveyor which includes a plurality of rollers arranged in parallel to each other, horizontally orientated and mounted to be freely rotatable, which rollers are aligned to the suction devices and grippers, however, are moved below the stack on a substantially rectilinear and horizontal path. Hereby the movements of the rollers and the suction devices are adjusted in relation to one another such that the suction device may grip the lowermost printed product of the stack between two successive rollers and may draw out its edge region, wherein the upstream roller of the two may move in-between the printed product gripped by the suction device and the printed product resting thereupon. The roll bed conveyor, thus, forms a succession of extraction openings orientated in parallel to the rollers and the printed product edges gripped by the suction devices, which openings successively move beneath the stack. In order for the stack to be securely supported and for the extraction openings to be large enough all the same, it is suggested to move the rollers beneath the stack in groups of three, wherein the rollers within the groups of three are at smaller distances from each other and wherein between succeeding groups a larger interspace is provided and only this interspace is used as extraction opening.
The rollers forming the roll bed conveyor underneath the stack consist of two mutually aligned roller sections, which are at a distance from each other. Thus, it is prevented that the suction devices conflict with the rollers. A circulating chain is provided on each side of the carrier wheel, one for the left roller sections and one for the right roller sections, wherein the roller sections are coupled to these chains and revolve with the chain at constant distances. The circulating path of the chains on both sides runs around a deflection roller arranged coaxially to the carrier wheel and around a further deflection roller with a parallel axis, which is arranged such that an upper part of the circulating paths is approximately horizontal between the deflection rollers. The stack is arranged above this region of the circulating path of the rollers.
The device according to EP-1226083, thus, includes a revolving roll bed conveyor with extraction openings, wherein the stack is arranged on the outside of this roll bed conveyor. For separation of the printed products from the stack the printed products are drawn through an extraction opening to the inner side of the circulating roll bed conveyor, from where they need to reach its outer side for being conveyed further. For this purpose the roller sections in the corresponding region are rotated into a substantially vertical position in their circulating path. In this region the printed products are laid down on a conveying belt and released by the grippers, wherein the conveying belt follows the circular movement of the grippers in a substantially tangential manner.
The device described in publication EP-1226083 works without problems and without requiring much space. It is, however, a costly device, which is restricted in connection with the direction of onward transportation.
The invention thus has the object of creating a device for the same purpose as the device described above according to EP-1226083, which is, however, relevantly more simple. Furthermore the device according to the invention is to be more flexible concerning the onward transportation, without requiring additional means.